“一步式合并”和“两步式合并”都是公司私有化的途径。

一步式合并即由上市公司控股股东持有的公司的子公司，与上市公司直接合并。合并后，上市公司非关联股东取得现金对价（“私有化对价”）并被挤出（Squeeze-out），上市公司成为控股股东控制的私人公司，并退市。一步式合并是私有化的最直接的方式。目前多数中国概念股公司私有化采用了一步式合并。一步式合并的缺点是，投票说明（Proxy Statement）在向股东发出之前须经过美国证监会（SEC）审查，这会延长私有化完成时间。

其英文释义如下：

A merger involving a public target in which the buyer acquires control of the target through a tender offer and a stockholder vote. Because generally a stockholder vote must be done via a SEC-regulated proxy solicitation process, a one-step merger can take considerably longer than a two-step merger, which can be accomplished without a stockholder vote if the tender offer reaches the statutory threshold (generally 85% to 90%) of shares tendered.

两步合并也称“要约收购(tender offer or exchange offer)”。首先，收购方直接向目标公司股东发出收购要约，各股东自行决定是否以要约方给出的价格出售其股份；接着，目标公司召开股东大会，审议与收购方合并的事宜，若获得大多数股东支持，则随即进行合并。由于此类交易结构需进行上述两步，因而被称为两步合并。

其英文释义如下：

A hybrid method of acquiring a company by combining a tender offer with a merger. In the first step, the buyer initiates a tender offer to acquire at least a majority of the outstanding target company’s stock. In the second step, the buyer completes a back-end merger to acquire the balance of the target company’s stock.

虽然大多数两步合并中的收购方会事先和目标公司董事会沟通，并在签署合并协议后进行收购，但是两步合并不要求董事会通过合并协议/收购要约，因而许多敌意收购便是采用两步合并方式。此外，如果能够采用短式合并方式执行两步合并，则能够极大缩短交易签署至交易完成所需时间，从而增加交易确定性。

全现金收购中，两步合并较为常见；而若涉及新股发行或是预期监管审批需时较长的话，则常用一步合并。

以下为相关双语示例，供参考：

The goal of a two-step merger is the same as that of a one-step merger: the target will become a wholly owned subsidiary of the acquiror. However, the merger agreement in a two-step merger requires the acquiror’s subsidiary to commence a tender offer for all of the target’s shares within a few days of signing the merger agreement. The primary timing advantage of the two-step transaction is that the acquiror may commence the tender offer without prior SEC review. A two-step merger with all cash consideration may be completed in as little as 30-40 days if the acquiror is able to effect a “short-form” back-end merger.

两步式合并的目标与一步式合并的目标相同：目标将成为收购方的全资子公司。但是，两步式合并中的并购协议要求收购方的子公司在签署并购协议的几天内开始对目标公司的所有股份进行要约收购。两步交易的主要时间优势是收购方可以在未进行SEC事先审查的情况下开始要约收购。如果收购方能够实现“简易形式”的后端并购，则全现金对价并购中的两步式并购可能能够在短短30-40天内完成。